The present invention relates generally to hand-held communication devices such as mobile telephones, pagers, or the like, and more particularly, to a hand-held communication device employing navigation key-based predictive text entry.
Wireless hand-held communication devices, in particular mobile telephones, have typically employed a twelve-key numerical keypad, providing the numbers 0 through 9 and the star (“*”) and pound (“#”) symbols. Where text entry is desired, such as in mobile telephones providing SMS (Short Message Service), EMS (Enhanced Message Service), MMS (Multi-media Message Service) messaging or IM (Instant Message) capability, one or more non-numeric characters (e.g., the letters of an alphabet, logographic symbols, or the like) are mapped to keys of the numeric keypad. For example, in mobile telephones providing text entry using the English alphabet, the letters “A” though “Z” are mapped to the numeric keys “2” though “9.” In this manner, all twenty-six letters of the English alphabet are accommodated by the twelve keys of the keypad to furnish alphanumeric text entry. However, using such character mapping techniques, multiple taps of the keys of the keypad are often required for entry of a non-numeric character, greatly increasing the time required for text entry.
As a result, predictive text entry techniques such as Tegic Communication's T9 text entry, Eatoni Ergonomics' LETTERWISE text entry, and the like, have been developed for entering non-numeric text using a twelve-key numeric keypad. Such predictive text entry techniques attempt to predict which letter mapped to a particular key of the keypad is most likely to be selected when the key is pressed during entry of text. In this manner, the number of key taps required to enter non-numeric text is reduced compared to conventional multi-tap text entry.
Often, it is desirable to provide hand-held communication devices, particularly mobile telephones, having extremely small form factors or aesthetically pleasing shapes. In such hand-held communication devices, the provision of a conventional twelve-key numeric keypad is often either impossible or undesirable. Consequently, the hand-held communication devices typically rely on menu driven displays and voice-recognition technologies such as voice-dialing and voice-entered commands in combination with a simple navigation key assembly instead of a full twelve-key keypad. However, in such devices, text messaging, if supported, requires extensive scrolling through a fixed character menu, and repeated keystrokes to select characters for a text message being composed.
Consequently, it is desirable to provide a predictive text entry using only the navigation and selection controls (e.g., two, four or five-way navigation keys, track wheels, jog dials, joy sticks, or the like) of a navigation key assembly that is suitable for use with hand-held communication devices having a highly reduced set of keys, such as, for example, mobile telephones that do not include a traditional twelve-key numeric keypad.